12,713 research outputs found
-decay half-lives of neutron-rich nuclei and matter flow in the -process
The -decay half-lives of neutron-rich nuclei with are systematically investigated using the newly developed fully
self-consistent proton-neutron quasiparticle random phase approximation (QRPA),
based on the spherical relativistic Hartree-Fock-Bogoliubov (RHFB) framework.
Available data are reproduced by including an isospin-dependent proton-neutron
pairing interaction in the isoscalar channel of the RHFB+QRPA model. With the
calculated -decay half-lives of neutron-rich nuclei a remarkable
speeding up of -matter flow is predicted. This leads to enhanced -process
abundances of elements with , an important result for the
understanding of the origin of heavy elements in the universe.Comment: 14 pages, 4 figure
Non-vanishing spin Hall currents in disordered spin-orbit coupling systems
Spin currents that flow perpendicular to the electric field direction are
generic in metals and doped semiconductors with spin-orbit coupling. It has
recently been argued that the spin Hall conductivity can be dominated by an
intrinsic contribution which follows from Bloch state distortion in the
presence of an electric field. Here we report on an numerical demonstration of
the robustness of this effect in the presence of disorder scattering for the
case of a two-dimensional electron-gas with Rashba spin-orbit interactions
(R2DES).Comment: 4 pages, 3 figure
Investigation of metal flow in bridge die extrusion of Alloy 6063 and subsequent effect on surface quality and weld seam integrity
This paper describes a detailed study of tube extrusion by simulation using finite element method (FEM). The finite element model used one-sixth of symmetry. The extrusion load, emperature evolution and metal flow were predicted. Innovative methods, combining both grid and surface tools, were used to define in detail the flow of material. These showed clearly the inner and outer surface formation mechanisms of the tube extrusion. The seam weld, an important quality indicator, was also evaluated by selecting an appropriate criterion
Vanishing viscosity limits for the degenerate lake equations with Navier boundary conditions
The paper is concerned with the vanishing viscosity limit of the
two-dimensional degenerate viscous lake equations when the Navier slip
conditions are prescribed on the impermeable boundary of a simply connected
bounded regular domain. When the initial vorticity is in the Lebesgue space
with , we show the degenerate viscous lake equations
possess a unique global solution and the solution converges to a corresponding
weak solution of the inviscid lake equations. In the special case when the
vorticity is in , an explicit convergence rate is obtained
Influence of metal elements on the evolution of CO and CH4 during the pyrolysis of sawdust
Metal elements in biomass ash have been considered to affect the decomposition of large molecule during the pyrolysis of biomass. In this paper, effect of metal elements on the evolution of carbon monoxide (CO) and methane (CH4) was investigated during the pyrolysis of sawdust in a fixed bed reactor and species were detected by Fourier Transform Infrared analyzer. Results showed that all the metal additions restrained the yields of CO and CH4 and the quantity order of production was Fe2O3<ZnO<NaCl<CaO<KCl< Al2O3<No-addition. The addition of Al2O3, Fe2O3 and ZnO shortened the completion time of CO and CH4. Statistical analysis demonstrated that all the metal additions lowered the reaction rate of biomass pyrolysis dynamically
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